Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true, readOnlyHint=false, and idempotentHint=false, so the safety profile is partly known. Beyond that, the description adds nothing: it does not say what format the archive uses, whether existing archives are overwritten, or what happens on failure mid-compression — meaningful context for a destructive, non-idempotent operation.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single front-loaded sentence with no filler; 'into a new archive' usefully signals the output side effect. The terseness itself is fine, though the brevity leaves the other gaps unfilled.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a destructive, non-idempotent 3-parameter tool with no output schema and zero parameter documentation, the description is far too thin. An agent cannot tell how paths are resolved, whether the archive name is derived or overwritten, or what a successful response looks like.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate for three undocumented required parameters (id, root, files). It only indirectly hints at 'files'; the meaning of 'id' and 'root' (and root's default '/') is left entirely unexplained, so the agent must guess at path resolution semantics.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific verb ('compress') and resource ('files') and mentions the output ('a new archive'), so the action is understandable. However, it does nothing to distinguish this from the obvious inverse sibling files_decompress or to clarify scope relative to the many other files_* operations.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance on when to use this instead of alternatives, whether it requires a path-based listing, or what happens if the archive already exists. The agent must infer everything from the parameter names alone.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.